36 turtles tagged in St. Eustatius

Our in-water survey of sea turtles and their habitats in St. Eustatius (a.k.a. “Statia”) was very successful. We aimed to collect data to analyse the habitat use and population connectivity of green and hawksbill turtles as part of a larger NWO research program encompassing the 6 Dutch Caribbean Islands.

Together with STENAPA (National Park authority of St Eustatius) and volunteers, and support from CNSI (Caribbean Netherlands Science Institute) we spend 2 weeks in the water (and 1 on the nesting beaches, see other blog-post). We snorkeled many hours to do turtle/habitat surveys and covered the west coast of Statia 2 times (from Venus bay to the botanical gardens). Once we spotted a resting sea turtle, we attempted to catch it while free diving for measurements & sampling. In addition we also catched turtles at dawn and dusk at some of Statia’s wrecks (Chien tong, Stenapa reef) as turtles are gathering there to sleep. As turtles often rest in deep areas (e.g. 25 meters at wrecks) we often used a combination of divers and free divers as an efficient way to catch multiple turtles.

Once on the boat turtles were measured, sampled and some sub-adult turtles were deployed with satellite transmitters (fastloc Splash10) to follow their habitat movements and dive profiles. This was the first time in-water work on Statia was attempted. Although conditions were not always ideal, especially due to the deep foraging grounds, we look back at a very successful field campaign. We especially thank STENAPA staff and intern Jessica, Melvina, Nadio, Eric, Clarissa, Elly for their great efforts during the in-water work. See video’s and photo’s below!

The time-lapse video is not great but gives you an idea of the 1.5 hr process it takes. it includes sandpapering & cleaning the carapace, attaching the tag on with epoxy, drying and painting the tag with black antifouling (not visible in video) before releasing the turtle back into the water.

after 1 day she was still happily swimming around at the same divesite. But now with some bling and a fancy Fastloc GPS transmitter, see below.

More updates on the positions of these turtles will be shared soon on this blog. ­­­­­­­­­­­­­­­­­­­­Sponsors who are committed to sea turle conservation and who want to support the project, can adopt one of the sea turtles with a transmitter on their back, name them and share its tracks. All proceeds from the adoption program go to STENAPA’s turtle program. Call for more information the STENAPA office +599 318 2884

me and Jessica (STENAPA turtle program coordinator, and WIDECAST country coordinator) with the first turtle we caught at St. Eustatius, a small juvenile green turtle

Left: snorkeler sees turtle during transects. Right: free diver attempts to catch turtleJuvenile green turtle with its new flipper tag waiting to be releasedHawksbill turtle waiting to be sampled

Transects above deep (22m) seagrass meadows. All seagrass meadows observed were dominated by invasive seagrass Halophila stipulaceaReturning one day in the St. Eustatius harbor: 1 hour of heavy rain results in mud slides. Sediment from eroded cliffs are deposited in the sea.Deploying a fast loc GPS satellite transmitter to a sub-adult green turtle. The red epoxy will later be covered with a black antifouling layerDeploying a fast loc GPS satellite transmitter to a sub-adult green turtleIkea bags are handy for weighing small turtlesA second turtle is deployed with a satellite transmitter. STENAPA staff are trainedReleasing turtle during early morning turtle survey (5:00)

Chien tong wreck is surrounded by meadows of invasive seagrass Halophila stipulaceaThe team (L->R) in front of STENAPA office: Jessica Berkel, Laurent Thieulle, Marjolijn Christianen, Elly, Funci, Fionne Kiggen, Mervina, Eric Houtepen, Nadio (not on picture)Seagrass around the New Star Petroleum terminalMud slides running down from eroded cliffs at St. Eustatius harbor. It was only raining for 1 hourSediment is run-off into the see. This increased in the hours to come. For the next 4 days the visibility around the island was terrible.

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Marjolijn Christianen

Assistant Professor @WUR, Blogs about fieldwork & events during her current research projects on sea turtles in the Dutch Caribbean, on food webs and ecosystem restoration in the Wadden Sea & about her completed PhD project on seagrass & green turtle grazing. She also provides practical info on her previous fieldwork site: Derawan in East-Kalimantan, Indonesia